Preview image is not updating in Facebook

I have updated my thumbnail image and preview-image of my HTML template which got approved today. It showing all okay in Themeforest. But when I share the link of my template, But when I share this item on facebook, the preview-image fetched by facebook is not the updated one. It keeps showing the previous image that it had. I tried clearing my browser cache - but no issue there. What might cause the problem?

This is the item :

They’re taken from Facebook CDN. So, you need to wait for about 2-3 days to see new images.